Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: rense
  • Order by date
  1. rense

    Hypothetical components in DW Sim

    can't you contact the developer ? see your other thread for site https://www.eng-tips.com/viewthread.cfm?qid=457439 about your question, it would be better to provide more information about your problem, depending from problem, you may know the properties of a chemical (critical, volumetric...
  2. rense

    LPG blend in a closed vessel

    www.google.com/search?q=chemputers1994.pdf as alternative you may wish to consider simplified models, with these you can try to compute the integral analytically (solving differential mass balances at specified conditions), an example is the Rayleigh equation but several other cases are...
  3. rense

    LPG blend in a closed vessel

    you know the initial conditions (compositions and volume of vessel), at each time step you subtract a predefined amount (vapor and/or liquid phase) , from mass balance calculate and define the new composition (remember you have fixed volume for vessel and different specific volumes for vapor /...
  4. rense

    LPG blend in a closed vessel

    you know initial composition and, from mass balance, you can calculate compositions (vapor and liquid at equilibria) at different time steps, a simple model could be based on ideal gas law and vapor pressure of different components but if you need accurate results consider a EOS, with simple...
  5. rense

    Help : HYSYS Properties of Liquid-Aqueous Mixture

    Iomcube, Not sure if that is what you are looking for but there is a simple Excel page which calculates the properties in different zones (see image) it works with all versions of Prode Properties, including free...
  6. rense

    VLE equilibrium/physical properties validation of a multicomponent system (CO2-MEA-H2O) inAspenPlus?

    perhaps you can estimate binary fractions based on definition of loading, for carbon dioxide, monoethanolamine and water ternary probably you need a model with support for electrolytes as the E-NRTL , however these models are complex including many equilibrium contants and I doubt you can...
  7. rense

    Help : HYSYS Properties of Liquid-Aqueous Mixture

    the normal procedure is to divide exchanger in zones and then calculate conditions and transport proerties in each zone, with those values you can estimate velocities, Prandtl Numbers (or equivalen parameters and so on...) for that you need to solve phase equilibria at specified H (with a H-P...
  8. rense

    Help : HYSYS Properties of Liquid-Aqueous Mixture

    simulators can include several models for mixtures, for example my copy of Prode Properties includes several models discussed in The Properties of Gases and Liquids (which I adopt as reference in many cases). Many different rules have been proposed (in literature) for example, for ideal liquid...
  9. rense

    Very high pressure gas relief - supercritical - Z>2

    I have used the integral method (HEM model) in Prode for pressures up to 900-1000 Bar, in principle there are no limits but I never found such high values (3000 Bar) as reported for this application..
  10. rense

    Calculation of Fan work by VdP and the adiabatic process where PV^(gamma) = Constant; which is OK?

    it is difficult to provide comments without knowing what you are doing, show us your calc's in both cases (for example for air) and someone may help.
  11. rense

    Control Valve two-phase flow with PRODE software

    when sizing for two phase flow you can expect higher errors, don't know the very last ISA edition but, according my knowledge, ISA formulations are not reliable for two phase flow, when possible I ask manufaturer to provide calc's, anyway there are a few methods as HNE-DS which may be...
  12. rense

    Depressurization Fundametal

    most simulators solve a blowdown mainly from a thermodynamic point of view, meaning at n steps (P initial->P final) a mass & heat balance is solved in the way suggested by T2k, to understand how it works you can solve for example a series of H-V flash or some equivalent operations, being...
  13. rense

    Vapor pressure and boiling point of liquid mixture

    to start you can adopt the same procedures but calculating fugacity of vapor and liquid phase with a EOS such as Peng Robinson or Soave, this requires some initialization for vapor and liquid compositions (see Wilson correlation for example) Details are discussed in many books, for example The...
  14. rense

    Process optimization

    yes, you should be more specific, however I have utilized Matlab in union with a thermodynamic library (Prode Properties) for simple problems, Matlab includes good minimizers but you need to compile in order to get reasonably fast executions. Another possibility is that you compile and link with...
  15. rense

    Specific vapor and liquid enthalpies in multi-component systems

    possibly you can validate yourself the solution, as first step check predicted densities for vapor and liquid phases then get compositions for liquid and vapor phase at equilibria since for vapor and liquid H = SUM(Wi*Hi) where Wi is weight fraction of component i and Hi is enthalpy of component...
  16. rense

    Specific vapor and liquid enthalpies in multi-component systems

    check the values predicted for density of vapor and liquid phases, while I agree that, in general, for vapor and liquid in equilibria Hvapor > Hliquid there may be specific conditions or wrong roots selected by the procedure
  17. rense

    relief temperature

    for fire case with vapor only, under certain conditions (predicted stress above critical values) a simple rupture disc (burst disc) may result a relatively inexpensive and reliable solution.
  18. rense

    relief temperature

    of course we all agree on that
  19. rense

    relief temperature

    Dejan, reading your post it seems that you consider the constant volume procedure applicable to vapor state only, but the blog shows an application of the method for vapor + liquid, in fact Prode solves the V-P flash operation with multiphase equilibria, note that a free version is available...
  20. rense

    relief temperature

    for vapor phase (no vapor-liquid equilibria) you do not need a simulator, you may estimate temperature inside vessel assuming constant Z Pin*Vin=Zin*R*Tin Prel*Vrel=Zin*R*Trel and since Vin = Vrel Trel = Tin * Prel / Pin where in is initial condition and rel is release condition this method is...

Part and Inventory Search